Apparatus for manufacturing solid double layer sheet glass

ABSTRACT

An apparatus is provided for manufacturing solid double layer sheet glass by fusing together the longitudinal and transverse edges of single sheets drawn vertically through a tunnel oven, having a lower guide track to support and guide the lower edges of the sheets, an upper, vertically adjustable guide track to guide the upper edges of the sheets, and a fusing device which is vertically adjustable relative to sheet height and serves to fuse the upper edges of the sheets.

United States Patent l 3,870,499 Stehl 1 Mar. 11, 1975 APPARATUS FORMANUFACTURING 3.201056 9/1965 Rocttcr ct a] .r 65/58 SOLID DOUBLE LAYERSHEET CLASS [76] Inventor: Otto Stehl, Brucker Holt 46, D Kellogg EssenBredeney Germany [22] Filed: Feb. 20, 1974 [2!] Appl No.: 444,185 [57]ABSTRACT I I An apparatus is provided for manufacturing solid dou-Apphumm prmmy ble layer sheet glass by fusing together the longitudinalM111 1973 (wrmlmy 3314715 and transverse edges of single sheets drawnvertically through a tunnel oven, having a lower guide track to U-S- (ll65/156, 65/160 upport and guide [he lower edges of [he 5hee[5 an v r r 4uppgr vertically adjustable guide truck to guide [58] new of Search65/587 160 upper edges of the sheets, and a fusing device which isvertically adjustable relative to sheet height and serves {56]References cued to fuse the upper edges of the sheets.

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APPARATUS FOR MANUFACTURING SOLID DOUBLE LAYER SHEET GLASS BACKGROUND OFTHE INVENTION The manufacture of solid double layer sheet glass byfusing single sheets along their longitudinal and transverse edgespresupposes a very exact guidance of the sheets within the zones inwhich the preliminary heating and then the actual processing take place.In known devices designed to carry out the heating, the fusing, thecooling of such sheets, individual vertical glass sheets are introducedto lower and upper guide tracks, whereupon they are transported througha tunnel oven, usually on slide or roller devices comprising the lowerguide track.

ln order to be able to guide the sheets with exactitude at both lowerand upper edges, it is necessary to adjust the distance of the upperguide track from the lower guide track in conformity with the height ofthe glass sheets. To this end, it is conventional in known devices toadjust the whole upper guide track as one integral unit relative toheight in such a way that secure guidance of the upper sheet edges isassured. As soon as the upper guide track has been adjusted at adetermined distance relative to the lower guide track, the fusing device(consisting of a burner arm) for fusing the upper sheet edges isadjusted accordingly, whereupon sheets of predetermined height may thenbe processed by means of the apparatus.

If sheets having a different height from that of an existing run of aparticular sheet height are to be produced, the entire production lineof sheets at the existing sheet height being conveyed through the ovenmust leave the tunnel oven, and the'guidetracks at the exit end of theapparatus, before the continuous upper guide track together with theburner arm can be readjusted to conform to the new sheet height.Furthermore, because the readjustment of the entire continuous upperguide track in such apparatus is not possible without a lengthyinterruption of the operation of the production line, such known devicesare suitable only for the economical production of large orders; whereasprocessing of a small order in which only a relatively small number ofsheets of a stated sheet height are to be produced, is uneconomicalbecause of the labor costs or set-up time arising from the readjustmentof the upper guide track.

The production of a small order of, for example, fifty pieces (and suchshort batches are inevitable in meeting production quotas in awindowglass factory) requires 2 hours oven time. Readjustment for thenext batch of a different sheet height takes roughly half an hour withprior art devices of the type described.

lt is therefore self-evident that there would be much advantage inhaving a devicethat could be adjusted for height without the time-lossrequired to adjust for different sizes of glass.

The time-consuming readjustment of sheet height has the followingadditional economic disadvantage in devices of the prior art. If, forexample, an order of 100 pieces of identical dimensions is to besupplied, several extra sheets must always be produced in order toaccount for rejects or production waste. Accordingly, there aregenerally a few sheets left over which cannot be disposed of. A devicein which the adjustment of sheet height does not require any additonaltime can be helpful in remedying this problem, because it permits thesubsequent replacement of only the defective pieces in a given batch ofthe pieces being processed.

SUMMARY OF THE INVENTION The basic object of the present invention is toprovide a device of the above-described type which permits theeconomical production of solid double layer sheet glass even in smallbatches and in fact even in individual sheets.

In accordance with the present invention an upper guide track issubdivided into mutually independent, vertically adjustable portions orsections whose length in the direction of the production linesubstantially corresponds to the maximum length of individual sheets tobe fused.

This facilitates independent readjustment of the upper guide track insections according to the height of the individual sheet that happens atthat moment to be inside a given section. For example, the section ofthe upper guide track lying in front of the tunnel oven entrance may beinitially adjusted to a given initial sheet height. After the subsequent(adjacent) guide track section which is already inside the tunnelovenhas discharged the individual sheet of possibly different heightwhich was also in the oven, this subsequent guide track section isbrought to the same level as that of the guide track section lying atthe tunnel oven entrance, whereupon the pair of single sheets may moveinto said first guide track section which is inside the tunnel oven.After the two have come together as a solid double layer glass sheet forfusing in the first guide track section within the oven, then the guidetrack section in front of the oven entrance may be again readjusted toaccommodate individual sheets of possibly different height. Theindividual sheets can be tranported out of the first guide track section(which is located in the heating station within the oven) into thesecond guide track section within the oven as soon as the latter guidetrack section (after the forwarding of the previous sheet which may haveexhibited a different height) has been adjusted to the level of thesheet now inside the first guide track. section within the oven.

This mode of operation facilitates the processing of small batches oreven individual double layer glass sheets in an economical manner,without having to stop the machine and interrupt production.

DESCRlPTlON OF THE PREFERRED EMBODIMENTS In accordance with onepreferred embodiment, the individual guide track sections areautomatically, vertically, adjustable dependent on respective sheetheights of individual glass sheets by means of respectivedrivemechanisms connected with each guide track section. It is at the sametime advantageous that each guide track section be automaticallyheight-adjustable dependent on the respective setting of the guide tracksection preceding it in forward sequence. It is further advantageous inaccordance with the present invention that the individual guide tracksections are controlled by sensing devices to determine relativeheight-adjustment of two subsequent guide track sections, and toequalize the adjustment of the guide track section next along theproduction line relative to that which preceded it. The sensing devicescan be limit switches applied to vertical switching strips arranged inpairs relative to each other.

Said limit switches influence the drive mechanisms causing equalizationof height-adjustment.

A particularly advantageous embodiment of the in vention as set forthabove is characterized by a plurality of supporting frames arrangedabove the upper guide track and above the tunnel oven, by means of twospindle drives actuated by a drive motor independently height-adjustablerelative to each other, and corresponding in their length substantiallyto the maximum length of the sheets which are to be fused. From saidsupporting frames there extend downwardly into the tunnel oven two guidesupport pins, to which the upper guide track segments are secured andsupported. Each guide track segement is rigidly connected at one endthereof with one of the guide support pins, and at the other end withthe other guide support pin in slidably track segment. In addition, avertical switching strip movable relationship in the direction of theconveyer. 1

By this means it is possible to absorb the heat expansion of the guidetrack segments, which, for example, consist of bracing tubes withattached guide rails secured to the two guide support pins.

Because the guide support pins (against which the guide track segmentsare hung) thermally lengthen or shorten during the height adjustment ofthe guide track segments (during height adjustment the portion of theguide support pins inside or outside the tunnel oven varies), it isadvantageous to provide means for continuous fine-height-adjustment ofthe individual guide track segments dependent on the relative positionof each individual guide track segment relative to the sheet it happensto be guiding at the moment. By such means the relative position of therespective upper guide track segments with respect to the upper edge ofeach glass sheet, is continually controlled. For example, with the guidetracks depending from a vertically adjustable bracing tube, by means ofthe fine-height-adjustment of the relevant guide track segment, itbecomes possible to carefully provide that the sheet edges are alwayslying correctly in the guide tracks at the proper elevation with respectto the tracks.

The mode of operation of the aforesaid device is further improved if forevery guide track segment a sensing device is provided to determine theposition of each respective segment, the sensing device controlling thefurther advancement of the glass sheets in coordination with the meansfor the adaptation of height adjustment in neighboring guide tracksegments. These sensing devices, which are preferably in the form of airgates, feed signals to a central control unit indicating when a certaingiven guide track segment does not carry a glass sheet. This signal theninitiates the height adjustment of the said guide track segment in sucha way that said segment is adjusted to the level of the precedingsegment which contains a sheet of determined height, whereuponsubsequently the sheet or sheets which until then occupied the precedingguide track segment are further advanced into the properlyheight-adjusted and adapted guide track segment.

The fusing device for the fusing of the upper sheet edges is in the formof an automatically heightadjustable torch arm which adjusts relative tothe height of each respective sheet. Coarse adjustment and fineadjustment for the height of the torch arm may also be provided at thisjuncture. The coarse adjustment is preferably actuated in such a waythat the torch arm is automatically height-adjustable dependent on theheight adjustment of the neighboring, preceding guide may be connectedto the torch arm, said switching strip being coordinated with limitswitches which are hooked up with a corresponding switching strip of theguide track segment preceding said torch arm, and said limit switchesserving to adapt the height adjustment of the torch arm to those of thepreceding guide track segment. For fine height-adjustment of the torcharm dependent on the relative position of said torch arm relative to theupper glass sheet edge, it is possible to proceed in similar fashion asfor the fine adjustment of the guide track segments, dependent on therelative position of the segments with respect to the upper sheet edge,by providing a sensing device which responds to the position of thetorch arm relative to the upper glass sheet edge. Then, the signalswhich represent deviation of the upper sheet edge from its predeterminedsetting actuate (by means of a motor attached to the torch arm, whichmay be constructed similar to the device for height adjustment of theguide track segments) a continuous vertical regulation of the torch armin accordance with the height level of the upper glass sheet edge.

The foregoing and other features and objects of the invention will bemore apparent from the following more detailed description, taken inconjunction with the accompanying drawings which form an integral partthereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 represents a longitudinal sideelevation, partly in section, showing a portion of a tunnel oven inaccordance with this invention with a continuous lower guide track andfive upper guide track segments which are at varying levels;

FIG. 2 represents a side elevation of a portion of a typical upper guidetrack suspension shown in FIG. 1;

FIG. 3 represents a right end elevation of the guide track segment shownin FIG. 2, partly in section;

FIG. 4 represents an enlargement of a portion of FIG. 2, showing variouspositions-of a guide track in relation to glass sheet; and

. FIG. 5 represents a partial view of various positions of the uppertorch arm with air gates connected to it for fine adjustment.

As shown in FIG. 1, the apparatus of this invention comprises a tunneloven designated overall by reference numeral 10, through which glasssheets 12 are guided on a lower guide track 14 consisting of rollers.The upper edges of sheets 12 are guided in an upper guide trackconsisting of individual segments or stations which in their severalentireties are generally designated at the top of FIG. 1 by referencenumerals 16, 18, 20, 22 and 24.

on occasion, as shown by the dotted lines in FIG. 1 (segment 16), it ispossible that two shorter glass sheets may simultaneously connect witheach guide track segment.-

Each of the guide track segments 16 through 24 consists, as mayspecifically be seen in FIGS. 1, 2 and 3 of a horizontal bracing tube 26on which is mounted a guide strip 28 (consisting of three individualstrips), which effectively provide two upper guide means for everyindividual sheet of the double layer sheet being manufactured. Bracingtube 26 is braced against two guide support pins 30 and 32, so as to berigidly connected with guide support pin 30, while on the other hand,slidably connected to the other guide support pin 32 to permitlongitudinal movement of tube 26 with respect thereto and yet givevertical support for the tube. Guide support pins 30 and 32 are bracedand guided by a frame 34 which is arranged above the level of the coverof tunnel oven 10, while the individual guide support pins 30 and 32 areguided through corresponding sliding bearings 36 at frame 34. The upperends of guide support pins 30 and 32 connect respectively with ahorizontal support frame 38 which may be elevated or lowered by means ofboth a drive motor 42 and two gears 44 which actuate vertical spindles40 respectively.

The suspension of individual bracing tubes 26 relative to guide supportpins 30 and 32 may be more readily understood from FIG. 2. As may beseen in this representation, each of the bracing tubes 26 is rigidlyconnected with guide support pin 30 as by means of screws or bolts 48.If bracing tube 26 should expand during heating in the directionindicated by the arrow (rightwards, in FIG. 2) then a correspondingdisplacement of bracing tube 26 for the compensation of this thermalexpansion is made possible by the fact that bracing tube 26 is notrigidly connected with the second guide support pin 32, but slidablymounted relative to said guide support pin 32. This slidable mounting ismade possible by rollers 50 (shown in FIG. 3), which can roll back andforth in longitudinal direction on a mounting surface 52 which isconnected with and carried by guide support pins 32. By this means anydislocation of bracing tubes 26 and of guide tracks 28 mounted thereonis avoided during temperature changes in the tunnel oven, so as toinsure that the glass sheets are guided from track segment to tracksegment precisely and in an exactly straight path.

As shown in FIG. 1, the preferred embodiment for height adjustment ofthe individual guide track segments 16-24 includes a coarse adjustmentmeans for adjusting each guide track segment dependent on the setting ofthe preceeding guide track segment, as well as a means for fineadjustment of each guide track segment dependent on the setting of guidestrips 28 relative to the upper edge of glass sheets 12. The coarseadjustment of guide track segment 18 relative to guide track segment 16,for example, includes two limit switches 56 and 58 attached at the endof a switching strip 54 carried by one frame 38, said limit switchesbeing acted upon by means of a switching strip 60 which actuates themdirectly and is connected with guide track segment 16 by means of theother frame 38. Similar devices are also provided between guide tracksegments of 18 and 20, and 22, 22 and 24, etc.

For the fine adjustment of the guide track segments with respect to therelative position of the upper sheet edge, air gates 62 and 64 areemployed, as shown in FIGS. 3 and 4. Another air gate 66 is provided fordetermination of the occupancy status of each respective provided tofuse together the upper vertical sheet edges dependent on the positionof guide track segment 20. In a manner similar to that described forvertical adjustment of the guide track segments, torch arm 68 iscontinuously adjusted by means of two limit switches 70 and 72 and acorresponding switching strip 74 at guide track segment 20, depending onthe position of guide track segment 20, to achieve a coarse adjustment.A fine adjustment is then obtained by means of two air gates 76 and 78depending on the position of the upper glass sheet edge relative toburner nozzles 80 (FIG. 5). Air gates 76 and 78 operate in a mannersimilar to airgates 62 and 64.

Drive motors 42 with gears 44 and spindles 40 (for the height adjustmentof individual guide track segments), as well as the drive for the heightadjustment of torch arm 68 are operationally connected with the severalsensing devices 54, 56, 58, 60; 62, 64, 66; 70, 72, 74; 76, 78, and withthe drive for the advancement of sheets 12 in forward direction throughthe oven by means of a central control unit, in such a way that thecoarse adjustment, fine adjustment, and height adjustment of guide tracksegments 16 through 24 as well as of torch arm 68 and the forwardadvancement of the sheets is achieved after appropriate level-adjustmentof the individual components.

The apparatus thus described operates in the following manner:

As soon as guide track segment 16 (which is at the entrance to tunneloven 10) has been adjusted to a height corresponding to the height ofglass sheets 12 which are about to be fused together, the glass sheetsare picked up by the guide means. As shown in FIG. 1, at this point intime there is no sheet left in guide track segment 18, so that the openair gate 66 signals that guide track segment 18 is unoccupied.

Thereupon guide track segment 18 moves downwardly, following the signalemitted by open limit switch 56 which signals that guidetrack segment 18is standing too high relative to guide track segment 16, causing segment18 to move downwardly until both limit switches 56 and 58 are actuatedby switching strip 60. This indicates that guide track segments 16 and18 are now at substantially the same level. As soon as the correspondingsignal is given, via limit switches 56 and 58, to the central controlunit (thereby announcing that sheets 12 can be further advanced), glasssheets 12 are moved ahead from guide track segment 16 into guide tracksegment 18. Finally, air gate 66 signals that guide track segment 18 isloaded so that further sheet advancement is blocked.

At the time of the downward movement of guide track segment 18, guidesupport pins 30 and 32 (to which bracing tube 26 is fixed) expand inconsequence of heating as they progress downwardly into the more intenseheat of the oven. At the same time, sheets 12 themselves expand in theopposite direction as soon as they have been moved out of guide tracksegment 16 and into guide track segment 18, in other words into theoven, with the result that optimal height-adjustment of guide strips 28relative to sheets 12 is no longer en sured, without further adjustment.

In consequence of the above-described relative motion of sheet 12 inrelationship to guide strips 28, air gate 62 is closed, whereupon drivemotor 42 for the height adjustment of support frame 38 pushes guidetrack segment 18 upwardly until air gate 62 is opened,

which signals the optimum height of segment 18 in relation to the glasssheet height, whereupon guide strips 28, are secured in the propervertical position.

In like manner the level of guide track segment 20, which is shown asset too low in FIG. 1, is adapted to the adjusted setting of guide tracksegment 18. In addition, guide track segment 20 will travel upwardlyuntil limit switches 56 and 58, in conjunction with switching strip 60,signal an equal level for guide track segments 18 and 20, so that theglass sheets (after a corresponding unloaded signal has been receivedfrom air gate 66 of guide track segment 20) may be advanced from guidetrack segment 18 into guide track segment 20. Because support pins 30and 32 of guide track segment 20 are withdrawn further out of tunneloven 10, they contract, so that guide strips 28 stand too high in thissegment in relationship to the upper edge of the glass sheets. At thispoint airgate 64 is opened, whereupon guide track segment 20 is loweredby means of drive motor 42 far enough to shut air gate 64 once more. Theforegoing operations are successively repeated in all of the followingguide track segments.

After the glass sheets have reached guide track segment 20 and therebyhave reached the point of readiness for fusing, the upper torch arm 68must be vertically adjusted so as to be at the correct height. For thispurpose the actuated limit switch 70 causes torch arm 68 to travelupwardly until both limit switches 70 and 72 are actuated by means ofswitching strip 74. When the corresponding signal is delivered to thecentral control unit, then sheets 12 are moved forward into fusingposition. Because the welding process requires a very precise setting ofthe upper torch arm 68 relative to the upper sheet edge, the coarseadjustment by means of limit switches 70 and 72 is followed by a fineadjustment by means of air gates 76 and 78. The precise relativepositioning of the torch arm relative to the sheet edge is achieved ifair gate 76 is opened and air gate 78 is interrupted. lf air gate 76 isat the same time interrupted, an unacceptably low positioning of thetorch arm 68 is indicated, which causes said torch arm to move upwardlyuntil air gate 76 opens once more. If, however, air gate 78 is opened,this signifies that torch arm 68 is positioned too high, whereupon saidtorch arm 68 is moved downwardly until air gate 78 is once againinterrupted.

Resort may be had to such modification and equivalents as fall withinthe spirit of the invention and the scope of the appended claims.

What is claimed and desired to be secured by Letters Patent is:

1. Apparatus for the manufacture of all-glass double windowpanes bywelding the longitudinal and transverse edges of single panes carriedupright through a tunnel oven, having a lower guide track for thesupport and guidance of the lower pane edges, a vertically adjustableupper guide track for the guidance of the upper pane edges, and fusingmeans that is adjustable in height according to the pane height forfusing the upper, horizontal pane edges, the upper guide track beingdivided into sections which are each automatically and verticallyadjustable independently of one another by means of a driving deviceassociated with each guide track section according to the height of theparticular pane therein contained, the length of said sections in theconveying direction being substantially the same as the length of theindividual panes to be fused together, each guide track section furtherhaving means for sensing the relative heights of any two adjacent guidetrack sections and for equalizing the vertical position of the guidetrack section next following in the direction of conveyance to that ofthe preceding one.

2. The apparatus of claim 1, wherein the sensing means are limitswitches arranged on vertical switching strips disposed and coordinatedin tandem, the positioning of the limit switches regulating drivedevices for vertical adjustment of the guide track sections.

3. The apparatus of claim 1, wherein a plurality of supporting framesare disposed above the guide track sections and above the tunnel oven,which are vertically adjustable independently of one another by a drivemotor through two spindle drives each, which are elongated in thedirection of conveyance of the panes, and which correspond in theirlength substantially to the maximum length of the panes to be fused, andfrom each of which two guide support pins extend downwardly into thetunnel oven, the upper guide track sections being fastened thereto.

4. The apparatus of claim 3, wherein means is provided for thecontinuous fine height adjustment of the individual guide track sectionsin accordance with the relative position of each guide track sectionwith respect to the pane that is guided on it, the said means having airgates for sensing the relative position of the particular guide tracksection with respect to the top edges of the panes.

5. The apparatus of claim I, wherein a torch arm is provided for fusingtogether the upper pane edges, which is automatically and verticallyadjustable in accordance with the particular pane height and there isassociated with said torch arm a vertical control rail having limitswitches which cooperate with a corresponding control rail of the guidetrack section preceding the torch arm for matching the height adjustmentof the torch arm to that of the preceding guide track section. I

1. Apparatus for the manufacture of all-gLass double windowpanes bywelding the longitudinal and transverse edges of single panes carriedupright through a tunnel oven, having a lower guide track for thesupport and guidance of the lower pane edges, a vertically adjustableupper guide track for the guidance of the upper pane edges, and fusingmeans that is adjustable in height according to the pane height forfusing the upper, horizontal pane edges, the upper guide track beingdivided into sections which are each automatically and verticallyadjustable independently of one another by means of a driving deviceassociated with each guide track section according to the height of theparticular pane therein contained, the length of said sections in theconveying direction being substantially the same as the length of theindividual panes to be fused together, each guide track section furtherhaving means for sensing the relative heights of any two adjacent guidetrack sections and for equalizing the vertical position of the guidetrack section next following in the direction of conveyance to that ofthe preceding one.
 1. Apparatus for the manufacture of all-gLass doublewindowpanes by welding the longitudinal and transverse edges of singlepanes carried upright through a tunnel oven, having a lower guide trackfor the support and guidance of the lower pane edges, a verticallyadjustable upper guide track for the guidance of the upper pane edges,and fusing means that is adjustable in height according to the paneheight for fusing the upper, horizontal pane edges, the upper guidetrack being divided into sections which are each automatically andvertically adjustable independently of one another by means of a drivingdevice associated with each guide track section according to the heightof the particular pane therein contained, the length of said sections inthe conveying direction being substantially the same as the length ofthe individual panes to be fused together, each guide track sectionfurther having means for sensing the relative heights of any twoadjacent guide track sections and for equalizing the vertical positionof the guide track section next following in the direction of conveyanceto that of the preceding one.
 2. The apparatus of claim 1, wherein thesensing means are limit switches arranged on vertical switching stripsdisposed and coordinated in tandem, the positioning of the limitswitches regulating drive devices for vertical adjustment of the guidetrack sections.
 3. The apparatus of claim 1, wherein a plurality ofsupporting frames are disposed above the guide track sections and abovethe tunnel oven, which are vertically adjustable independently of oneanother by a drive motor through two spindle drives each, which areelongated in the direction of conveyance of the panes, and whichcorrespond in their length substantially to the maximum length of thepanes to be fused, and from each of which two guide support pins extenddownwardly into the tunnel oven, the upper guide track sections beingfastened thereto.
 4. The apparatus of claim 3, wherein means is providedfor the continuous fine height adjustment of the individual guide tracksections in accordance with the relative position of each guide tracksection with respect to the pane that is guided on it, the said meanshaving air gates for sensing the relative position of the particularguide track section with respect to the top edges of the panes.